# I need help on the moment equation here please

1. Feb 9, 2016

### Brendan Webb

• Thread moved from the technical forums, so no HH Template is shown.
I have come to the point in the equation where I need the moment equation to solve for Ay. I am not sure how to get By in term of Ay though. The moment equation I get for Ay is:

∑Mb = 8(-P2) - 20(-P1) - 32(Ay) + 15Ax

I know P1 = 270 - P2

However I am not sure if I even have Ay and Ax right in the ∑Mb equation. Where do I go from here?

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2. Feb 9, 2016

### Semkan

Because of the boundary conditions in points A and B, TotalMb and TotalMa should be zero. You could write two different equations from here, and 2 more equations comes from TotalFy and TotalFx. And here you go, you have 4 equations and 4 unknowns, which you can solve for all the unkowns

3. Feb 9, 2016

### Brendan Webb

Do i have the ΣMb equation right if I wrote it equal to 0?

Ok so for the Fy = 0 equation it would be -Ay -P1 - P2 +By = 0

For the Fx = 0 equation it would be -Ax + Bx = 0 (However, is Ax and Bx the total force across the cable or are the broken up into three components?)